Information processor, image forming apparatus, information processing method, and non-transitory computer-readable medium

Abstract

An information processor includes a storage unit storing a first coefficient in correspondence with a characteristic of a sheet of paper, a first acquisition unit acquiring a first signal based on the water content of a first sheet of paper not having an image formed thereon, a second acquisition unit acquiring a second signal based on the water content of the first sheet of paper having an image formed thereon and being heated for fixing, a determination unit determining the characteristic of the first sheet of paper, a first calculation unit calculating a variation in water content of the first sheet of paper using the difference between the first signal and the second signal and the first coefficient stored in correspondence with the determined characteristic, and a second calculation unit calculating an expansion and contraction ratio of the first sheet of paper using the variation in water content.

What is claimed is: 
     
       1. An information processor comprising:
 a storage unit that stores a first coefficient, which is preset on the basis of the relationship between a water content of a sheet of paper and a signal output from a signal output unit on the basis of the water content when a sheet of paper having each characteristic has the water content, in correspondence with the characteristics; 
 a first acquisition unit that acquires a first signal output from the signal output unit on the basis of the water content of a first sheet of paper not having a first image formed thereon; 
 a second acquisition unit that acquires a second signal output from the signal output unit on the basis of the water content of the first sheet of paper which has the first image formed on a first surface thereof and which is heated to fix the first image; 
 a determination unit that determines the characteristic of the first sheet of paper; 
 a first calculation unit that calculates a variation in water content of the first sheet of paper using the difference between the acquired first signal and the acquired second signal and the first coefficient stored in correspondence with the determined characteristic in the storage unit; and 
 a second calculation unit that calculates an expansion and contraction ratio of the first sheet of paper using the variation in water content calculated by the first calculation unit. 
 
     
     
       2. The information processor according to  claim 1 , wherein the storage unit stores a second coefficient, which is preset on the basis of the relationship between the variation in water content of a sheet of paper and the expansion and contraction ratio of the sheet of paper when the water content of a sheet of paper having characteristics varies by the variation, in correspondence with the characteristics, and
 wherein the second calculation unit calculates the expansion and contraction ratio of the first sheet of paper using the second coefficient stored in correspondence with the determined characteristic in the storage unit. 
 
     
     
       3. The information processor according to  claim 2 , wherein the second coefficient includes a coefficient regarding the expansion and contraction ratio in a first direction of a sheet of paper and a coefficient regarding the expansion and contraction ratio in a second direction of the sheet of paper. 
     
     
       4. The information processor according to  claim 1 , wherein the storage unit stores the variation in water content calculated by the first calculation unit, and
 wherein the second calculation unit calculates the expansion and contraction ratio of the first sheet of paper using an average of the variation in water content stored in the storage unit. 
 
     
     
       5. The information processor according to  claim 2 , wherein the storage unit stores the variation in water content calculated by the first calculation unit, and
 wherein the second calculation unit calculates the expansion and contraction ratio of the first sheet of paper using an average of the variation in water content stored in the storage unit. 
 
     
     
       6. The information processor according to  claim 3 , wherein the storage unit stores the variation in water content calculated by the first calculation unit, and
 wherein the second calculation unit calculates the expansion and contraction ratio of the first sheet of paper using an average of the variation in water content stored in the storage unit. 
 
     
     
       7. The information processor according to  claim 1 , further comprising a measuring unit that measures a temperature around the signal output unit,
 wherein the first calculation unit calculates the variation in water content of the first sheet of paper using the temperature measured by the measuring unit. 
 
     
     
       8. The information processor according to  claim 2 , further comprising a measuring unit that measures a temperature around the signal output unit,
 wherein the first calculation unit calculates the variation in water content of the first sheet of paper using the temperature measured by the measuring unit. 
 
     
     
       9. The information processor according to  claim 3 , further comprising a measuring unit that measures a temperature around the signal output unit,
 wherein the first calculation unit calculates the variation in water content of the first sheet of paper using the temperature measured by the measuring unit. 
 
     
     
       10. The information processor according to  claim 4 , further comprising a measuring unit that measures a temperature around the signal output unit,
 wherein the first calculation unit calculates the variation in water content of the first sheet of paper using the temperature measured by the measuring unit. 
 
     
     
       11. The information processor according to  claim 5 , further comprising a measuring unit that measures a temperature around the signal output unit,
 wherein the first calculation unit calculates the variation in water content of the first sheet of paper using the temperature measured by the measuring unit. 
 
     
     
       12. The information processor according to  claim 6 , further comprising a measuring unit that measures a temperature around the signal output unit,
 wherein the first calculation unit calculates the variation in water content of the first sheet of paper using the temperature measured by the measuring unit. 
 
     
     
       13. An image forming apparatus comprising:
 a signal output unit that outputs a first signal corresponding to the water content of the first sheet of paper not having a first image formed thereon and a second signal corresponding to the water content of the first sheet of paper which has the first image formed on a first surface thereof and which is heated to fix the first image; 
 a storage unit that stores a first coefficient, which is preset on the basis of the relationship between a water content of a sheet of paper and a signal output from the signal output unit on the basis of the water content when a sheet of paper having each characteristic has the water content, in correspondence with the characteristics; 
 a first acquisition unit that acquires the first signal output from the signal output unit; 
 a second acquisition unit that acquires the second signal output from the signal output unit; 
 a determination unit that determines the characteristic of the first sheet of paper; 
 a first calculation unit that calculates a variation in water content of the first sheet of paper using the difference between the acquired first signal and the acquired second signal and the first coefficient stored in correspondence with the determined characteristic in the storage unit; 
 a second calculation unit that calculates an expansion and contraction ratio of the first sheet of paper using the variation in water content calculated by the first calculation unit; 
 a correction unit that either corrects the size or position of a second image formed on a second surface of the first sheet of paper on the basis of the expansion and contraction ratio calculated by the second calculation unit, or corrects an image to be formed on a second surface of a second sheet of paper; and 
 an image forming unit that forms the first image on the first surface of the first sheet of paper, heats the first sheet of paper to fix the first image, and forms the corrected second image on the second surface of the first sheet of paper. 
 
     
     
       14. The image forming apparatus according to  claim 13 , wherein the signal output unit outputs the first signal and the second signal through the use of a single device,
 wherein the correction unit corrects an image to be formed on a second surface of a second sheet of paper, 
 and wherein the image forming unit forms the corrected image on the second surface of the second sheet of paper after forming an image on the first sheet of paper. 
 
     
     
       15. The image forming apparatus according to  claim 14 , wherein the image forming unit forms an image in accordance with an image forming condition,
 wherein the image formed on the first sheet of paper is a test image used to adjust the image forming condition, and 
 wherein the image formed on the second sheet of paper is an image other than the test image. 
 
     
     
       16. An information processing method in an information processor having a storage unit that stores a first coefficient, which is preset on the basis of the relationship between a water content of a sheet of paper and a signal output from a signal output unit on the basis of the water content when a sheet of paper having each characteristic has the water content, in correspondence with the characteristics, the method comprising;
 acquiring a first signal output from the signal output unit on the basis of the water content of a first sheet of paper not having a first image formed thereon; 
 acquiring a second signal output from, the signal output unit on the basis of the water content of the first sheet of paper which has the first image formed on a first surface thereof and which is heated to fix the first image; 
 determining the characteristic of the first sheet of paper; 
 calculating a variation in water content of the first sheet of paper using the difference between the acquired first signal and the acquired second signal and the first coefficient stored in correspondence with the determined characteristic in the storage unit; and 
 calculating an expansion and contraction ratio of the first sheet of paper using the variation in water content calculated by the first calculation unit. 
 
     
     
       17. A non-transitory computer-readable medium storing a program causing a computer to execute a process, the computer including a storage unit that stores a first coefficient, which is preset on the basis of the relationship between a water content of a sheet of paper and a signal output from a signal output unit on the basis of the water content when a sheet of paper having each characteristic has the water content, in correspondence with the characteristics, the process comprising:
 acquiring a first signal output from the signal output unit on the basis of the water content of a first sheet of paper not having a first image formed thereon; 
 acquiring a second signal output from the signal output unit on the basis of the water content of the first sheet of paper which has the first image formed on a first surface thereof and which is heated to fix the first image; 
 determining the characteristic of the first sheet of paper; 
 calculating a variation in water content of the first sheet of paper using the difference between the acquired first signal and the acquired second signal and the first coefficient stored in correspondence with the determined characteristic in the storage unit; and 
 calculating an expansion and contraction ratio of the first sheet of paper using the calculated variation in water content.